Trialkylamine oxides are known to have excellent foaming properties which would render their use in toilet bars highly desirable (Kamen et al. U.S. Pat. No. 3,562,167). Such trialkylamine oxides are conventionally made by reacting a trialkylamine having at least one detergent range alkyl group with aqueous hydrogen peroxide. The trialkylamine oxide that forms has a tendency to form gels in the aqueous reaction medium. Because of this, it has been necessary in the commercial production of trialkylamine oxides to limit their concentrations to no more than about 30 weight percent (e.g., Ammonyx LO, 30 weight percent aqueous lauryl dimethylamine oxide, Onyx Chemical Co.). Attempts to form a more highly concentrated product causes the reaction mixture to gel making it essentially unstirrable. Because of this, use of trialkylamine oxides in applications where water addition must be limited is prohibited. Such applications are exemplified by use. The addition of only 10 weight percent trialkylamine oxide as a 30 percent aqueous solution would concurrently introduce about 23 weight percent water into the detergent bar resulting in a paste which would require further drying. The only known alternative would be to remove water from the trialkylamine oxide solution either before mixing it with the other components in the formulation which appears to be the method used in Poper et al. U.S. Pat. No. 4,290,904, because Ammonyx LO used in its examples is a commercial 30 weight percent lauryl dimethylamine oxide solution sold at one time by Onyx Chemical Co., or, after blending it with the other components, followed by a water removal step, as shown in Yoshikawa U.S. Pat. No. 4,320,033. These alternate methods are high energy consumers leading to a prohibitive economic penalty. A need exists for a process for making detergent bars containing detergent range trialkylamine oxide without the use of dilute aqueous solutions of the trialkylamine oxides and without the necessity of driving off large amounts of water from the heat sensitive trialkylamine oxide solution or from the toilet bar formulation made with it.